APPCOR11778

• Permit No: C1981071
• IBM Index Class Name: Application Correspondence
• Doc Date: 8/26/1985
• From: CYCC
• To: BLM
• Media Type: D
• Archive: No

•
• - • III IIIIIIIIIIIIIIII
999
{
Colorado Yampa Coal Company
August 26, 1985
Mr. Jerry Strahan
Craig District Office
Bureau of Land Management
Sox 246
455 Emerson Street
Craig, Colorado 81625
Dear Mr. Strahan:
29588 Routt County Road #27, Oak Creek. CO 80467 • [phone]
Please find the enclosed information regarding the reduction of certain
reserves at Colorado Yampa Coal Company (CYCC) in a mine area referred to as
"Area 60". The reduced tonnage lies entirely in Federal Coal Lease #C-081330.
This information is in reference to earlier requests concerning documentation
of such a reduction. Also included is a plan view map of the Area 60 re-
serves, a cross-section along this reserve area, a table containing relevant
drill hole information, and geophysical logs of these drill holes.
Recoverable reserves of 1,642,200 tons were originally estimated to be in
Area 60, Lease #C-081330. This area is delineated on the plan view map as
Area 60 - Old. The extent of this mine area was established on the northwest
boundary by maximum dragline digging depth, on the northeast and southwest
boundaries by major faulting, and at the southeast boundary by the crest of
the hillside. As illustrated by the corresponding cross-section, increasing
overburden depths and decreasing recoverable coal thicknesses are realized by
advancing to the northwest area boundary. These factors combine to cause the
strip ratios (CYD Overburden/Tons Co a1) to significantly increase from the top
of the mine area to the lower (northwest) end. Additionally, coal seams less
than 2.0 feet thick cannot feasibly be recovered with conventional surface
mining equipment at CYCC. Approximately 1/3 of the lower Area 60 - Old mine
area does not contain recoverable lower split coal, due to the thickness con-
sideration. This area is noted on the plan view map as "One Seam Recovery".
Included in the plan view map are locations of all cored holes, drilled
during 1983. This is the most accurate and consistent drilling information
available in Area 60. Other drill data has been collected; however, inconsis-
tencies between holes, poor core recoveries, and lack of geophysical logs
preclude their use. Please bear in mind that the drilling information pro-
vided is confidential and must be treated as such.
Due to only single seam recovery and increasing overburden depths in the
northwest end of the Area 60 - Old mine area, an economic pit limit analysis
was then performed. Historical operating costs combined with the available
• geologic data was utilized to estimate the total costs to recover coal in Area
60 - Old. The analysis was also performed on an incremental basis such that
the impact of the higher strip ratios in the northwest end could be evaluated.